A turbomachine, such as a steam turbine, has a housing within which a rotor of the steam turbine is mounted. In order that the housing can be opened, for example in order to remove the rotor from the housing, it has a horizontal parting joint such that the housing is divided in two, into a lower part and an upper part. In order to prevent leakage of the steam at the parting joint, it is necessary to provide sealing surfaces at the parting joint, both on the lower part and on the upper part, between which for example a sealing ring is inserted. By providing a flange, the lower part and the upper part can be screwed together and a predetermined contact pressure between the sealing surfaces can be generated.
When the steam turbine is in operation, the sealing surfaces are subjected to wear processes, such as erosion corrosion and stresses due to pressure and temperature gradients. Furthermore, vibration phenomena during operation of the steam turbine can lead to a relative movement between the lower part and the upper part, which can give rise to frictional corrosion on the sealing surfaces. The wear and/or the corrosion of the sealing surfaces leads to a reduction in sealing capability, such that in the end leakage of the steam can occur. Conventionally, both the lower part and the upper part are made of high-alloy steel, which is therefore expensive, in order to withstand the wear processes and in order to achieve a high strength of the lower part and of the upper part.